zencart allows adding downloadable products for sale where people can buy direct on your website and get the donload after paypal payment setup takes about 3 hour to get the hang of e.g. http://www.youtube.com/watch?v=JQfeu5Rbhvo http://www.youtube.com/watch?v=ekX-UrzkpoU http://zencart-ecommerce-website-design.com/index.php?main_page=page&id=13
http://www.google.com.au/#hl=en&source=hp&biw=1276&bih=546&q=zen+cart+downloadable+products
